What is the serum therapeutic range for digoxin?

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What is the serum therapeutic range for digoxin?

Digoxin has a very narrow therapeutic index, so monitoring its blood level helps ensure it’s effective without being toxic. The serum therapeutic range for digoxin is typically 0.5 to 2.0 ng/mL. Within this window, digoxin can improve symptoms of heart failure and help control ventricular rate in atrial fibrillation by enhancing myocardial contractility and increasing vagal tone. Measuring the level after the drug has reached steady state is important—often about 1–2 weeks after starting or adjusting the dose, with the test timed for a trough level (just before the next dose). Subtherapeutic levels (below 0.5 ng/mL) may not provide clinical benefit, while levels above 2.0 ng/mL raise the risk of digoxin toxicity, which can present with gastrointestinal symptoms, confusion, and dangerous heart rhythm disturbances. Factors such as renal function, age, electrolyte imbalances (notably low potassium or magnesium), and drug interactions can shift this range, so clinicians tailor monitoring to the individual.

Digoxin has a very narrow therapeutic index, so monitoring its blood level helps ensure it’s effective without being toxic. The serum therapeutic range for digoxin is typically 0.5 to 2.0 ng/mL. Within this window, digoxin can improve symptoms of heart failure and help control ventricular rate in atrial fibrillation by enhancing myocardial contractility and increasing vagal tone.

Measuring the level after the drug has reached steady state is important—often about 1–2 weeks after starting or adjusting the dose, with the test timed for a trough level (just before the next dose). Subtherapeutic levels (below 0.5 ng/mL) may not provide clinical benefit, while levels above 2.0 ng/mL raise the risk of digoxin toxicity, which can present with gastrointestinal symptoms, confusion, and dangerous heart rhythm disturbances. Factors such as renal function, age, electrolyte imbalances (notably low potassium or magnesium), and drug interactions can shift this range, so clinicians tailor monitoring to the individual.

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